package keypair;

//----------------------------------------------------------------------------
//$Id: RSAKeyPairRawCodec.java,v 1.2 2005/10/06 04:24:16 rsdio Exp $
//
//Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
//
//This file is part of GNU Crypto.
//
//GNU Crypto is free software; you can redistribute it and/or modify
//it under the terms of the GNU General Public License as published by
//the Free Software Foundation; either version 2, or (at your option)
//any later version.
//
//GNU Crypto is distributed in the hope that it will be useful, but
//WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with this program; see the file COPYING.  If not, write to the
//
// Free Software Foundation Inc.,
// 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301
// USA
//
//Linking this library statically or dynamically with other modules is
//making a combined work based on this library.  Thus, the terms and
//conditions of the GNU General Public License cover the whole
//combination.
//
//As a special exception, the copyright holders of this library give
//you permission to link this library with independent modules to
//produce an executable, regardless of the license terms of these
//independent modules, and to copy and distribute the resulting
//executable under terms of your choice, provided that you also meet,
//for each linked independent module, the terms and conditions of the
//license of that module.  An independent module is a module which is
//not derived from or based on this library.  If you modify this
//library, you may extend this exception to your version of the
//library, but you are not obligated to do so.  If you do not wish to
//do so, delete this exception statement from your version.
//----------------------------------------------------------------------------

import java.io.ByteArrayOutputStream;
import java.math.BigInteger;
import java.security.PrivateKey;
import java.security.PublicKey;

/**
* <p>An object that implements the {@link IKeyPairCodec} interface for the
* <i>Raw</i> format to use with RSA keypairs.</p>
*
* @version $Revision: 1.2 $
*/
public class RsaKeyPairRawCodec implements IKeyPairCodec {

// Constants and variables
// -------------------------------------------------------------------------

// Constructor(s)
// -------------------------------------------------------------------------

// implicit 0-arguments constructor

// Class methods
// -------------------------------------------------------------------------

// Instance methods
// -------------------------------------------------------------------------

// gnu.crypto.key.IKeyPairCodec interface implementation -------------------

@Override
public int getFormatID() {
   return RAW_FORMAT;
}

/**
 * <p>Returns the encoded form of the designated RSA public key according to
 * the <i>Raw</i> format supported by this library.</p>
 *
 * <p>The <i>Raw</i> format for an RSA public key, in this implementation, is
 * a byte sequence consisting of the following:</p>
 *
 * <ol>
 *		<li>4-byte magic consisting of the value of the literal
 *    {@link Registry#MAGIC_RAW_RSA_PUBLIC_KEY},<li>
 *		<li>1-byte version consisting of the constant: 0x01,</li>
 *		<li>4-byte count of following bytes representing the RSA parameter
 *		<code>n</code> (the modulus) in internet order,</li>
 *		<li>n-bytes representation of a {@link BigInteger} obtained by invoking
 *    the <code>toByteArray()</code> method on the RSA parameter <code>n</code>,</li>
 *		<li>4-byte count of following bytes representing the RSA parameter
 *		<code>e</code> (the public exponent) in internet order,</li>
 *		<li>n-bytes representation of a {@link BigInteger} obtained by invoking
 *    the <code>toByteArray()</code> method on the RSA parameter <code>e</code>.</li>
 * </ol>
 *
 * @param key the key to encode.
 * @return the <i>Raw</i> format encoding of the designated key.
 * @exception IllegalArgumentException if the designated key is not an RSA
 * one.
 */
@Override
public byte[] encodePublicKey(PublicKey key) {
   if (!(key instanceof RsaPublicKey)) {
      throw new IllegalArgumentException("key");
   }

   RsaPublicKey rsaKey = (RsaPublicKey) key;
   ByteArrayOutputStream baos = new ByteArrayOutputStream();

   // magic
   baos.write(Registry.MAGIC_RAW_RSA_PUBLIC_KEY[0]);
   baos.write(Registry.MAGIC_RAW_RSA_PUBLIC_KEY[1]);
   baos.write(Registry.MAGIC_RAW_RSA_PUBLIC_KEY[2]);
   baos.write(Registry.MAGIC_RAW_RSA_PUBLIC_KEY[3]);

   // version
   baos.write(0x01);

   // n
   byte[] buffer = rsaKey.getModulus().toByteArray();
   int length = buffer.length;
   baos.write( length >>> 24        );
   baos.write((length >>> 16) & 0xFF);
   baos.write((length >>>  8) & 0xFF);
   baos.write( length         & 0xFF);
   baos.write(buffer, 0, length);

   // e
   buffer = rsaKey.getPublicExponent().toByteArray();
   length = buffer.length;
   baos.write( length >>> 24        );
   baos.write((length >>> 16) & 0xFF);
   baos.write((length >>>  8) & 0xFF);
   baos.write( length         & 0xFF);
   baos.write(buffer, 0, length);

   return baos.toByteArray();
}

@Override
public PublicKey decodePublicKey(byte[] k) {
   // magic
   if (k[0] != Registry.MAGIC_RAW_RSA_PUBLIC_KEY[0]
         || k[1] != Registry.MAGIC_RAW_RSA_PUBLIC_KEY[1]
         || k[2] != Registry.MAGIC_RAW_RSA_PUBLIC_KEY[2]
         || k[3] != Registry.MAGIC_RAW_RSA_PUBLIC_KEY[3]) {
      throw new IllegalArgumentException("magic");
   }

   // version
   if (k[4] != 0x01) {
      throw new IllegalArgumentException("version");
   }
   int i = 5;

   int l;
   byte[] buffer;

   // n
   l = k[i++] << 24 | (k[i++] & 0xFF) << 16 | (k[i++] & 0xFF) << 8 | (k[i++] & 0xFF);
   buffer = new byte[l];
   System.arraycopy(k, i, buffer, 0, l);
   i += l;
   BigInteger n = new BigInteger(1, buffer);

   // e
   l = k[i++] << 24 | (k[i++] & 0xFF) << 16 | (k[i++] & 0xFF) <<  8 | (k[i++] & 0xFF);
   buffer = new byte[l];
   System.arraycopy(k, i, buffer, 0, l);
   i += l;
   BigInteger e = new BigInteger(1, buffer);

   return new RsaPublicKey(n, e);
}

/**
 * <p>Returns the encoded form of the designated RSA private key according to
 * the <i>Raw</i> format supported by this library.</p>
 *
 * <p>The <i>Raw</i> format for an RSA private key, in this implementation,
 * is a byte sequence consisting of the following:</p>
 *
 * <ol>
 *		<li>4-byte magic consisting of the value of the literal
 *    {@link Registry#MAGIC_RAW_RSA_PRIVATE_KEY},<li>
 *		<li>1-byte version consisting of the constant: 0x01,</li>
 *		<li>4-byte count of following bytes representing the RSA parameter
 *		<code>p</code> (the first prime factor of the modulus) in internet
 *    order,</li>
 *		<li>n-bytes representation of a {@link BigInteger} obtained by invoking
 *    the <code>toByteArray()</code> method on the RSA parameter <code>p</code>,</li>
 *		<li>4-byte count of following bytes representing the RSA parameter
 *		<code>q</code> (the second prime factor of the modulus) in internet
 *    order,</li>
 *		<li>n-bytes representation of a {@link BigInteger} obtained by invoking
 *    the <code>toByteArray()</code> method on the RSA parameter <code>q</code>,</li>
 *		<li>4-byte count of following bytes representing the RSA parameter
 *		<code>e</code> (the public exponent) in internet order,</li>
 *		<li>n-bytes representation of a {@link BigInteger} obtained by invoking
 *    the <code>toByteArray()</code> method on the RSA parameter <code>e</code>,</li>
 *		<li>4-byte count of following bytes representing the RSA parameter
 *		<code>d</code> (the private exponent) in internet order,</li>
 *		<li>n-bytes representation of a {@link BigInteger} obtained by invoking
 *    the <code>toByteArray()</code> method on the RSA parameter <code>d</code>,</li>
 * </ol>
 *
 * @param key the key to encode.
 * @return the <i>Raw</i> format encoding of the designated key.
 */
@Override
public byte[] encodePrivateKey(PrivateKey key) {
   if (!(key instanceof RsaPrivateKey)) {
      throw new IllegalArgumentException("key");
   }

   RsaPrivateKey rsaKey = (RsaPrivateKey) key;
   ByteArrayOutputStream baos = new ByteArrayOutputStream();

   // magic
   baos.write(Registry.MAGIC_RAW_RSA_PRIVATE_KEY[0]);
   baos.write(Registry.MAGIC_RAW_RSA_PRIVATE_KEY[1]);
   baos.write(Registry.MAGIC_RAW_RSA_PRIVATE_KEY[2]);
   baos.write(Registry.MAGIC_RAW_RSA_PRIVATE_KEY[3]);

   // version
   baos.write(0x01);

   // p
   byte[] buffer = rsaKey.getPrimeP().toByteArray();
   int length = buffer.length;
   baos.write( length >>> 24        );
   baos.write((length >>> 16) & 0xFF);
   baos.write((length >>>  8) & 0xFF);
   baos.write( length         & 0xFF);
   baos.write(buffer, 0, length);

   // q
   buffer = rsaKey.getPrimeQ().toByteArray();
   length = buffer.length;
   baos.write( length >>> 24        );
   baos.write((length >>> 16) & 0xFF);
   baos.write((length >>>  8) & 0xFF);
   baos.write( length         & 0xFF);
   baos.write(buffer, 0, length);

   // e
   buffer = rsaKey.getPublicExponent().toByteArray();
   length = buffer.length;
   baos.write( length >>> 24        );
   baos.write((length >>> 16) & 0xFF);
   baos.write((length >>>  8) & 0xFF);
   baos.write( length         & 0xFF);
   baos.write(buffer, 0, length);

   // d
   buffer = rsaKey.getPrivateExponent().toByteArray();
   length = buffer.length;
   baos.write( length >>> 24        );
   baos.write((length >>> 16) & 0xFF);
   baos.write((length >>>  8) & 0xFF);
   baos.write( length         & 0xFF);
   baos.write(buffer, 0, length);

   return baos.toByteArray();
}

@Override
public PrivateKey decodePrivateKey(byte[] k) {
   // magic
   if (k[0] != Registry.MAGIC_RAW_RSA_PRIVATE_KEY[0]
         || k[1] != Registry.MAGIC_RAW_RSA_PRIVATE_KEY[1]
         || k[2] != Registry.MAGIC_RAW_RSA_PRIVATE_KEY[2]
         || k[3] != Registry.MAGIC_RAW_RSA_PRIVATE_KEY[3]) {
      throw new IllegalArgumentException("magic");
   }

   // version
   if (k[4] != 0x01) {
      throw new IllegalArgumentException("version");
   }
   int i = 5;

   int l;
   byte[] buffer;

   // p
   l = k[i++] << 24 | (k[i++] & 0xFF) << 16 | (k[i++] & 0xFF) << 8 | (k[i++] & 0xFF);
   buffer = new byte[l];
   System.arraycopy(k, i, buffer, 0, l);
   i += l;
   BigInteger p = new BigInteger(1, buffer);

   // q
   l = k[i++] << 24 | (k[i++] & 0xFF) << 16 | (k[i++] & 0xFF) << 8 | (k[i++] & 0xFF);
   buffer = new byte[l];
   System.arraycopy(k, i, buffer, 0, l);
   i += l;
   BigInteger q = new BigInteger(1, buffer);

   // e
   l = k[i++] << 24 | (k[i++] & 0xFF) << 16 | (k[i++] & 0xFF) << 8 | (k[i++] & 0xFF);
   buffer = new byte[l];
   System.arraycopy(k, i, buffer, 0, l);
   i += l;
   BigInteger e = new BigInteger(1, buffer);

   // d
   l = k[i++] << 24 | (k[i++] & 0xFF) << 16 | (k[i++] & 0xFF) << 8 | (k[i++] & 0xFF);
   buffer = new byte[l];
   System.arraycopy(k, i, buffer, 0, l);
   i += l;
   BigInteger d = new BigInteger(1, buffer);

   return new RsaPrivateKey(p, q, e, d);
}
}
